Rolling mill inching device



April 15, 1958 J. R. sHlELDs ErAL 2,830,467

l ROLLING MILL INCHING DEVICE Filed June 15. 1955 6 sheets-sheet 1 j INVENToRs WMe-.s Fenosa: rue/ o5 Abril 15, 1958 J. R. sHn-:LDs ETAL v2,830,467

' ROLLING MILL INCHING bEvrcE e sheets-sheet -2 Filled June 15, 1955 April l5, 1958 Filed June 15, 1955 J. R. sHlELDs ETAL 2,830,467

ROLLING MILL INCHING DEVICE 6 Sheets-Sheet 3 mw ,wma

l Abril 15 1958 J. R. SHIELDs ETAL 2,830,467

ROLLING MILL INCHING DEVICE e sheets-sheet 4 Filed June 15, 1955 'United States l Patef noLLnso anni. INCHINGDEVICE James Rodger Shields and Eugene W. Barth, Pittsburgh,

and Kenneth Wayne Fitzsirnmons, Greensburg, Pa., assignors to Elliott Company, Xeanette, Pa., a corporation of Pennsylvania Application .lune 15, 1955, Serial No. 515,604 y l Claims. (Cl. 74--665) 4 of the spindles and rolls will match,.so that the wabblers can ',be connected together. The 'main drive for the mill yturns the spindles too fast for this purpose, so other means have to be provided for slowly rotating or inching thespindles. Heretofore, suchA means have been qufite expensive and sometimes not very satisfactory or sa e.

, Itis" among the objects of this invention to provide a rolling mill inching drive, whichV is mechanical and relatively small and inexpensive, which can'inch the spindles in?,r either forward or reverse direction, which cannot be actuated-whilethe main drive is operating, and vwhich includes means for preventing `operation ofthe main drive while the inching' mechanism is operating.

AIn accordance' with this invention, 1a bull gear is adapted to be operatively connected with the `spindles that turn the mill rolls. The spindles normally 'are driven by a main drive motor. A small .retractableidler gear is -adapted to mesh'with the bull gear, but normally they are spaced apart. Means is provided, independent of the motor, for driving the idler gear slowly so that when it is meshed with the bull gear by manuallycontrolled means', when the main drive is not operating, the spindles will Ibe, rotated'very slowly. Preferably, the idler gear is,-driven by'a drive pinion, 'andthe former is carried by afpivptally mounted cage which swings the idler gear into andout of 4mesh with theA bull gear. Means is provided which is actuated by the 'bull gear when Athe main drive starts, to assure separation'ofjthe'two gears.'r Whenthe idler gear is moved 'into mesh withthe bull1gear,the circuit to the-maindrive motor is opened. VTherealso is provided means actuated by the bull'gear as soon vas it starts `to be driven lby the main drive, for making it irn-v possible to .movefthe idler gear against the bllgear'a's long as the millis operating.

The preferred embodiment of the inventionis villustrated inthe accompanying drawings, in which:v

Fig. l is a schematic planr view ofa rolling mill and its drive; i

fFig. 2 is a greatly venlarged side view of the-inching mechanism; Fig., 3 is a vertical section taken on the line`III-III ofFig. 2; f

Fig. 4 is an enlarged vertical section of the lower part of the mechanism,taken on the line IV-IV of Fig. '2;

Pig. 5 is a'horizontal section of a detail taken on the line V-V of Fig. 4; I

Fig. 6 is a horizontal cross section'ltaken on'the line VI-VI ofFig. 4;,v v Y (Fig.V 7 -is anvenlarged vertical sectionfofr one of the controls taken on theline VII- VII of Fig. 3 and Fig. 8is an electricwiring diagram.

Referring to Fig. 1 of the drawings, the vertically spaced rolls 1 of a rolling mill are driven from a pinion stand 2 through spindles 3. The pinion stand is driven by a drive shaft 4 that is rotated by reduction gearing 5, which in turn is driven Iby a large electric motor 6 through a pinion shaft 7. In order to change the rolls, the spindles have to be disconnected from them. When the rolls are replaced, the wabbler connections 'between the ends of the spindles and rolls seldom are in position to interengage with each other, so the spindles must be rotated very slowly the number of degrees necessary to permit coupling. In accordance with this invention, this inching of the spindles is done by means of a mechanism or drive 8 that operates when the main motor 6 is not operating. At such times the reduction gearing is driven slowly by the inching mechanism through an extension 9 of the reductiongearing pinion shaft 7 on the sideof the gearing opposite the main motor.

As shown in Figs. 2 and 3, the inching drive includes a suitable base 11, on one end of which a gear housing 12 is mounted. In the upper part of this housing a large bull gear 13 is mounted on the end of shaft extension 9. While the inching mechanism is not operating, the bull gear serves no purpose but is driven likea llywheel' by shaft 9 at normal main motor speed. The bull gear can perform its intended function onlywhen the main motor is not operating. At such times the'spindles can be turned oververy slowly by driving them from the 'bull gear through shaft 9 and the reduction gearing." For this purpose the bull gear can be driven slowly in either direct tion by a small, reversible gear motor 14 'mounted on'the they are connected' to the cores of thecoilsl When a base of the mechanism at one side of housing 12'.

Iournaled in the lower part of housing 12 is a shaft 16 that is driven by the gear motor. Integral with this shaft is a drive pinion`17 that meshes with two small idler gears 13 and 19 located between'it and the lower part of the bull gear, as shown in Fig. 4. Idler gear 18 is journaled in the upper part of an inclined cage 21, the lower part of which straddles pinion 17 and is rockably mounted on pinion shaft 16. `The other idler gear 19-is'n1ounted'in a similar cage 22 extending at an angle of a littlemore than to Athe rst cage and having its lower e'n'dals'opivotally mounted on the pinion shaft independently of the other cagef YThe lower parts of the Vtwo cages aref staggered on` the shaft as shown in Fig. 6. e The upper sides of the cages' are open' so that they can extend into each other and to enable'the two gears to mesh with ftheI bull gear when desired. Normally both cages' are in their lower position, where they rest on screws23 mounted in theupper walls 24. of open-end chambers 'in the lower part of the housing'.l Y Y' y f Projecting from the upper ends of the cages are lugs 26 and 27 provided with holes, through which studsv 28"` and 29 extend. The lower ends lof the studs are lsecured in 'bosses 31 below the upper walls 24 of the underlyingk cham-bers. "Compressed between lug 26 and the adjacent boss is afcoil spring32 which takes the weight of cage 21 and its gear, but which is not strong enough to lift the cage, by itself. A similar 'but weaker spring 33 is compressed between lug 27`and a sleeve 34 onstud A29.

Extending downward from the lower ends of the cages are arms'36 provided'at their lowerends with slots that receive pins 37 on the outer ends of a pair'ofprod-s These rods are slidably mounted in the chamber en d walls; 39 and extend back into solenoid coils 41 and 42where coilis energized, by the closing of a manuallyactuatedl switch 43 (Fig. 8), the coil pulls the adjacent arm( 36 towardit and thereby, vwith thehelp of the coil spring above it, swings the adjoining` cage upward to ymesh-:the

- idler gearwith the bullgear.'V Once an idler startsfzt mesh with the bull gear, the forces on the idler gear are such that' a naturalmoment arises which holds its cage inposition as long as pinion 17 drives the idler. The gear motor then drives the bull gear and, because of the reduction through the bull gear and the mill-drive gearing,'. the spindles are driven at a very slow speed for inching them. For example, in` one'installation pinion 17` is driven at 28 R.V P. M. and drives the bull gear at aboutV 6 R. P. M. By the time the speed is reduced further through reduction gearing 5, the spindle speed is only about 1/4 R. P. M. i t

The direction of inching depends upon the direction of rotation of the gear motor and upon the particular idlerv gear that is moved into engagement with the bull gear. Duringinching. the right-hand idler 18 in Fig. 4 is used todrive the bull gear in a counterclockwise directon,.but it is driven in a clockwise direction by the other idler gear when the motor is reversed. Assuming that the direction of rotation of the bull gear during normal operation of the mill is inr a clockwise direction, `it will be seentthatify idler gear 19 does not drop away from the bull gearfafter inching, the'clockwise rotation of the bull gear when the main motor takes over will swing the left-hand cage down and thereby prevent the gear motor from being driven by the bull gear and ruined by the high speed main motor. l On.the other hand, if inching has been in the other direction and the other idler gear 18 hangs up against the bullk gear after the main motor is started, the rotation of the bullgear clockwise will tend to hold gear 18 in engagement with it. To prevent this from happening, a clutch pinion46 is mounted in one end of a clutch cage 47, the opposite end of which is `rockably mounted in a special bracket 48 in housing 12. Projectingfrorn the bottomof the cage is a pin 49 that engages a projecting arm 50 on the adjacent gear cage 21. The clutch pinion is part of an overrunning clutch and can turn only in a clockwise directionas viewed in IFig. 4. Therefore, `as longras the bull gear is being driven counterclockwise by the `gear '18, the clutch pinion will be rotated. However, as soon` as the bull gear starts to be driven clockwise by vthemain motor 6, the clutch pinion will stop rotating and therefore the bulkgear -will swing thatv pinion and its cage downward, which will force gear 18 away from the bull gear and thereby protect the small motor.

"In order to insure meshing of the clutch pinion with the bull gear when idler gear.18 is swung upward, so thatthe pinion cannot prevent the idler gear from meshing, steps are taken to have the rotating idler gear mesh with the bull gear land start it rotating before the latter is touched by the'clutch pinion. Accordingly, bracket 48 is rockably` mounted on top chamber wall 24 for moving clutch cage 47 toward and away from the bull gear in a substantially radial direction, andas the bull. gear is rotating when the clutch pinion engages it, the two quickly mesh together. The base of the bracket tits over a rocker pin 52 mounted in a groove in the top of wall 24, and while the clutch pinion engages the bull gear the bracket base between the pin and the idler cage rests flat on the supporting wall as shown. At that time the bottom of the bracket base behind the rod pin is inclined upward and outward. The bracket is held in that position by a heavy.` coil spring 53 connecting it witharm 50 of the adjacent idler cage. and'the clutch pinion `and itsv cage are swung down as explained in the preceding paragraph, the outer end of arm 50 will move toward bracket 48 and remove the tension from the spring. This will allow a coil spring 54 ona vertical stud 55, extending through an oversize hole in the base of the bracket and screwed into wall 24, to press the outer end of the bracket base down at against wall 24 as the inner end of the bracket ltilts up. The result is that the upper end of the bracket pulls the clutch pinion outward 'away from the bull gear. The endsof spring 53 are fastened to the bracket and arm 50 through slotted connections 56tthat lallow idler gear 18,

When solenoid 41 is deenergized.

4 when solenoid 41 is energized, to start to mesh with and drive the bull vgear before the spring begins to rock bracket 48 toward the bull gear. The bracket is held in Vposition on the rock pin by front and rear studs 57 and 58 extending loosely through holes in the bracket base and screwed into wall 24. The heads of these studs are spaced far enough from the wall to allow for the rocking movement of the bracket.

Another safety feature is that when a solenoid rod 38 is pulled into a coil, a lateral projection 61 (-Fig. 5) on the rod opens a normally closed electric switch 62 which opens the electric circuit to the main motor 6, so that it is impossible to start that motor during inching.

Of course, it is important that the inching mechanism solenoids 41 and 42 not be energized accidentally while the main motor is operating. To make certain that such an accident will not occur, the circuit of gear motor 14 contains a normally closed, fluid-pressure operated electric switchwhich isopened automatically as soon as the main motor 6. starts to operate. This switch 66, shown in Fig. 3, is opened by the pressure of a head of oil in a standpipe 67 (Fig. 7) inside of a tank 68 supported by the upper part of gear housing 12. The lower end of the standpipe,` is in communication with a hydraulic pump 69 submerged in oil and driven through a short shaft 71 from the center of the bull gear.` The lower part of the standpipe also is `connected through a pipe 72 with the switch 66, so that as soon as the level of the oil in the standpipe is high enough the weight of the oil will exert enough pressure to open the switch. The oil overflows the top of the standpipe and is recirculated. Part way down the side of the standpipe there is a small orice '73, which permits the oill 'above it to leak out of the pipe when the pump 'Estopa Consequently, a short time after the pump stops, the level of oil in the pipe falls far enough to permit' theswitch to close so that the inching mechanism lcan be operated.

The arrangement is such that enough oil will be pumped into the standpipe within three seconds after the main motor starts to` drive .the bull gear to open switch` 66. The switchI will remainV open un-til after the motor has stopped. Duringdeceleration of the bull gear, the standpipe will remain fullof oil until the bull gear speed has decreased to about l5 R. P. M., at which time the ow through oriiice 73 equals the pump discharge. From thereto zero R. P. M. the head of oil will fall, due to draining out through the orice, but at a varying rate depending on the rate of deceleration. 'The time delay thus incorporated in this safety system` should be 20 or 25 seconds, which means that the switch should not close untilthe motor has stopped, or perhaps 15 t seconds or so later. This can be controlled by the size of orifice 73;

IAccording to theprovisions of the patent statutes, we have explained the principle of our invention and' have illustra-ted and described what we now considerto represent its best embodiment: However, we desire to have ity understood that, within the scope of the appended claims,` the invention may be practiced otherwise than asspeciiically illustrated and described. t

We claim:

l. In atrolling mill having roll-driving spindles normally driven by a main drive, a mechanical inching drive for -the spindles comprising a bull gear operativelyf'connected` with the spindles and normally driven by said main drive, a small retractable idler gear adapted to mesh with the bull gear but normally spaced from it, means independent of said main drive for driving the idler gear slow1y,: and manually controlled means for meshing the idler gear with the bull gearv when said main drive is inoperative, whereby to permit 'the spindles tobe rotated slowly bysaid independent drive means while rolls are being installed in the mill.

v2.An inching drive as defined in claim l; including means'for swinging the` idler gear away from the bull gear and operated by rotation' of the bullgear when said main drive starts, to assure,separation of the idler "gear from the bull gear.`

3. An inching drive means actuated by, said manually controlled means adapted to renderthe main drive inoperative as long as the idler and bull gears areinmesh. j

4. rAn inching drive as defined in claim 1, Vincluding means actuated/by the bull gear, as soon as the main drive starts driving the bull gear,- for making it impossible'to operate said manallycontrolledmeans as long as the main drive-is operating..l f Y 5. Rolling mill apparatus comprising roll-driving spindles, a shaft operatively connected with the spindles for driving them, a `prime mover vfor normally driving the shaft, a bull Ygear Ioperatively connected with ythe shaft andrnormally driven thereby, a 'small retractable 4idler gear adapted to mesh with the r bulli ,gearr but normally spaced from it, means independent of said prime mover for drivingthe idler gear slowly, and manually controlled means for meshing the idler gear with the bull gear when said prime mover is not operating, whereby to permit the shaft to be driven slowly by said independent drive means while rolls are being installed in the mill.

6. In a rolling mill having roll-driving spindles normally driven by a main drive, a mechanical inching drive for the spindles comprising a bull gear operatively connected with the spindles and normally driven by said main drive, a small idler gear adapted to mesh with the bull gear but normally spaced from it, a drive pinion meshing with the idler gear, a cage carrying the idler gear and rockable around the axis of -the pinion, means independent of said main drive for driving the pinion slowly, and manually controlled means for swinging the cage toward the Abull gear to move the idler gear into mesh with it when said drive is not operating, whereby to permit the spindles to be rotated slowly by said independent drive means while rolls are being ins-talled inthe mill.

7. In a rolling mill having roll-driving spindles normally driven by a main drive, a mechanical inching drive for the spindles comprising a bull gear operatively connected with the spindles and normally driven by said main drive, a small idler gear adapted to mesh with the bull gear but normally spaced from it, a drive pinion meshing with the idler gear, a cage carrying the idler gear and rockable around the axis of the pinion, means independent of siad main drive for driving the pinion slowly, and electromagnetic means operatively connected with said cage for swinging it toward the bull gear to mesh the idler gear with the bull gear when said main drive is not operating,

`whereby to permit the spindles to be rotated by said independent drive means while rolls are being installed in the mill.

8. An inching drive as deiined in claim 6, including a pinion rotatable only one way and normally spaced from the bull gear, and means actuated vby said cage for moving said one-way pinion into mesh with the bull gear when the cage is swung toward it, the one-way pinion being rotatable by the bull gear only when the latter is driven by said idler gear, whereby reversal of the bull gear will cause said cage-actuated means to swing the cage and idler gear away from the bull gear.

9. A mechanical inching drive for the spindles of a rolling mill normally operated by a main drive, said inching drive comprising a bull gear adapted to be operatively connected with the spindles, a drive pinion below the center of the bull gear and spaced therefrom, a pair of cages having inner ends independently rockable around the axis of the pinion and extending laterally therefrom in opposite directions, a small idler gear journaled in the outer end of each cage and meshing with the pinion, said as dened in claim 1, including:V

driving said pinion to cause saidlast-mentionedidler gear to drive the bull gear.

connected with the spindles, a small retractabe idler gear adapted to Amesh with the bull gear but normally spaced from it, an electric motor, means operativelyv connecting said motor with the idler gear for driving the idler gear slowly, manually controlled means for meshing the idler gear with the bull gear when said main drive is inoperative, an electric switch in the motor circuit, and means responsive to the speed yof the bull gear for operating the' switch automatically when the bull gear is driven at a` predetermined speed by the main drive for opening the circuit to said motor. v

11. A mechanical inching drive for the spindles of a` rolling mill normally operated by a main drive, said inching drive comprising a bull gear adaptedto be operatively connected with thev spindles, a small retractable idler gear adapted to mesh with the bull gear but normal-- ly spaced from it, an electric motor, means operatively connecting said motor with the idler gear for driving the Vidler gear slowly, manually controlled means for meshing the idler gear with the bull gear when said main drive is inoperative, a normally closed switch in the circuit of s-aid motor, and uid pressure means that is operated when the bull gear is driven by the main drive for opening said switch.

12. A mechanical inching drive for the spindles of a rolling mill normally operated by a main drive, said inching drive comprising a bull gear adapted tobe operatively connected with the spindles, a small retractable idler gear adapted to mesh with the bull gear but normally spaced from it, an electric motor, means operatively connecting said motor with the idler gear for driving the idler gear slowly, manually controlled means for meshing the idler gear with the bul1 gear when said main drive is inoperative, a normally closed switch in the circuit of said motor, a standpipe provided with a side drain orifice, a conduit connecting the bottom of the standppe with said switch, and a pump operated by the bull gear for pumping liquid up into the standpipe and past said orifice when the bull gear is driven rapidly by said main drive, the head of liquid in the standpipe being adapted to open said switch.

13. A mechanical inching drive for the spindles of a rolling mill normally operated by a main drive, said inching drive comprising a bull gear adapted to be operatively connected with the spindles, a small idler gear adapted to mesh with the bull gear but normally spaced from it, a drive pinion meshing with the idler gear, a cage carrying the idler gear and rockable -around the axis of the pinion, means independent of said main drive for driving the pinion slowly, manually controlled means for swinging the cage toward the bull gear to move the idler gear into mesh with it when said main drive is not operating, an electric switch controlling the operation of the main drive, and means operating the switch when the cage is swung toward the bull gear for rendering the main drive inoperative.

14. A mechanical inching drive for the spindles of a rolling mill normally operated by a main drive, said inching drive comprising a bull gear adapted to be operatively connected with the spindles, Ia small idler gear adapted to mesh with the bull gear but normally spaced from it, a

t drive pinion meshing with the idler gear, a cage carrying the idler gear and rockable around the axis of the pinion, means independent of said main drive for driving cages normally holding said idler gears spaced from the bull gear, selective means for swinging either cage upward to mesh its idler gear with the bull gear when said main drive is not operating, and a reversible motor for means Vfor, renderinggthe: maindrive. inoperative:A as long-as the idler gear is meshing with thebullx gear;V g

15. `Armechanical, inching drive for the spindles ,of a rolling mill normally operatedl `by a main1drve,;y saidv inching `drive comprising a bully gear adaptedtobeoperatively connectedwith the spindles and to be-,drivenrby `the main drive in one direction, adrive pinionk belowl the center of the bull gear and-spacedtherefrom;` ak pair ofca'ges having inner ends independently rockable around the axis of the pinion and extending laterally therefrom in-A op;-

posite directions, a small idler gearjournaled in the outer` c f mally spaced from thebull gear, means'ifor moving said one-way pinioninto mesh with the bull gears aid onesway pinion-moving means being actuatedby the cage carry-1 one-,way pinionbeing rotatable bylfthe bull gear onlyV Whilevthe bulljgearis driven by said `adjacentidler gear, whereby reversal of the bullY gear by the main drive will cause said one-way piniommovingsmeans ,to` swing the adjoining cage and idler gear away from the bull gear.

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Maurer n Dec. 31,k 1935 

